The present invention relates to styrene polymers including homopolymers and copolymers having a new stereoregular structure and more particularly to styrene polymers in which the stereoregular structure of said chains relative to the polymer main chain is mainly syndiotactic.
As is well known, styrene homopolymers such as polystyrene and polyparamethylstyrene, and styrene copolymers are generally produced by technique such as radical polymerization, anionic polymerization, cationic polymerization and polymerization using Ziegler-type catalysts. These styrene polymers are divided into three groups, isotactic, syndiotactic and atactic polymers, depending on the steric configuration of side chains thereof. It has heretofore been known that usual radial, anionic and cationic polymerization methods provide styrene polymers having mainly an atactic structure, and that the polymerization methods using Ziegler-type catalyst provide styrene polymers having mainly an isotactic structure.